Problem: Evaluate the following expression when $c = 7$ and $d = 8$. $8$ $c$ $ + 3$ $d$ $ - 7$
Explanation: Substitute $7$ for ${c}$ and $8$ for ${d}$ $ = 8{(7)} + 3{(8)} - 7 $ $ = 56 + 24 - 7 $ $ = 73$